1. Field of the Invention
The invention is related to communication networks, and in particular, to call release systems and methods.
2. Description of the Prior Art
Advances in telecommunication technologies have allowed for the development of many new services. Often times, services are provided by what are commonly referred to as service platforms. For example, voicemail is a service provided by a service platform. When a caller wishes to retrieve his voicemail messages, his call is routed to a service platform. Another example of a service includes automated telephone banking. When a caller wishes to retrieve his bank account status, his call is routed to a service platform.
Tromboning, also referred to in the art as hair pinning, is a well known problem associated with service platform calls. Tromboning occurs when a call to a service platform is re-routed to another destination and the service platform remains in the call loop. FIG. 1 illustrates telecommunication system 100 in the prior art where a caller first calls a service platform and is then re-routed to another destination.
FIG. 1 includes caller 110, network 120, tandem switch 120, tandem switch 140, service platform 150, Incumbent Local Exchange Carrier (ILEC) 160, and destination platform 170. FIG. 2 illustrates tromboning in prior art telecommunication system 100.
In operation, a call is placed from caller 110 to service platform 150. The call is routed from caller 110 through network 120, tandem switch 130, and tandem switch 140, to service platform 150. The call is processed in service platform 150. For instance, service platform 150 could be a voicemail system providing voicemail services to the caller.
While processing the call, the voicemail system determines that the call needs to be re-routed to destination platform 170. Service platform 150 then out-dials the phone number for the call. The call is connected from service platform 150 through tandem switches 140 and 130 and ILEC 160 to destination platform 170. As illustrated, the call connection between caller 110 to destination system 170 is connected through service platform 150. Such tromboning takes up valuable resources in service platform 150 and in the system as a whole.
FIG. 3 illustrates Release Link Trunking in the prior art. Release Link Trunking is one prior art solution to the problem of tromboning. With Release Link Trunking, caller 110 is connected to service platform 150 through network 120 and tandem switches 130 and 140. Upon determining the call should be transferred to destination platform 170, service platform 150 signals tandem switch 140 with instructions to release the call leg between tandem switch 140 and service platform 150. The signaling also instructs tandem switch 140 that a new call leg is required to destination platform 170. The new call leg is setup from tandem switch 140 through tandem switch 130 and ILEC 160 to destination platform 170.
One problem with this solution is that tromboning still occurs in tandem switch 140. As illustrated, a first call leg for the call exists between tandem switch 130 and tandem switch 140. A second call leg from tandem switch 140 to tandem switch 130 folds back over the first call leg. Thus, tandem switch 140 remains in the call loop. Such a configuration wastes the resources of tandem switch 140, such as processing power and trunk capacity. Furthermore, tandem switch 140 may belong to a different carrier than that of switch 130. It would be desirable for a call to be released out of the carrier network of service platform 150 to the originating carrier's network.